The invention relates generally to imaging systems, and more particularly, embodiments relate to an apparatus and method for reducing image artifacts that are produced by movement of an object.
Multi-modality imaging systems exist that scan using different modalities, such as, for example, Computed Tomography (CT), Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), and Single Photon Emission Computed Tomography (SPECT). During operation, conventional imaging systems may exhibit image quality that is affected by motion of the object being imaged.
Motion of the object being imaged may degrade image quality, for example in medical imaging. More specifically, image artifacts are produced by movement of the object. Involuntary motion in mammals (e.g., people and animals) encountered in medical imaging systems is a common source of image artifacts. The involuntary motion may lead to errors, such as when a physician is determining the size of a lesion, determining the location of the lesion, or quantifying the lesion.
To correct for motion related imaging artifacts, at least one conventional imaging system utilizes a prior knowledge of areas that typically exhibit motion. For example, when imaging a patient, the motion of the diaphragm may cause motion related artifacts to be present in the image. One conventional method to compensate for diaphragm motion is to determine the location of the diaphragm and to use a prior knowledge of typical diaphragm movement to modify the scan acquisition protocol to compensate for the diaphragm motion. The patient is then imaged using the modified scan acquisition protocol. The a priori knowledge is typically based on the operator's knowledge of the quantity of expected diaphragm motion not on the actual movement of the specific patient diaphragm being imaged. Specifically, the conventional motion correction method relies on the assumption that the movement of the diaphragm is approximately the same for each patient. However, diaphragm motion varies from patient to patient. Another conventional method for determining motion utilizes an external sensor to detect motion. For example, the external sensor may sense the movement of the chest of a patient during the breathing cycle. However, the movement of the chest is generally different than the movement of the internal organs such as the diaphragm, for example. As a result, the conventional methods may not adequately determine the movement of internal organs and therefore may not adequately compensate for motion related artifacts in the image produced.